- Hits: 3164
Management of stocks of bridges structures and buildings are a key feature of civil engineering management in both the public and private sector. Structural assessment of these is a key skill. There is a growing need to re-use existing structures and buildings and to maximize their useful life through adaptation and strengthening. The module will provide students with analysis skills coupled with practical solutions and an understanding of the deterioration profiles of common materials. This paper discusses some of the major systems that can be applied in the management and assessment of structures in large organizations. There is also a discussion of some major defects that may occur in structures and the appropriate repair processes. The paper ends with a case study concerning the deterioration of steel making a railway bridge.
In civil engineering and structural mangement, the management of large bridges and buliding stocks are a very important feature in both the private and public sectors. The structural assessment for these stocks of buildings and bridges is a very important skill whereby everyone has to be competent enough (McKenzie, 2004). Because of these issues to do with the assessment and management of these stocks, there have been a growing requirement in re-using the existing buildings and structures in order to maximize their usability in life by their adaptation and eventful strengthening. With a decline in the budgetary allocations for the maintenance of building and infrastructure management, coupled with the increased rate of aging of the management systems of present day infrastructure, a lot of challenges in the maintenance of high performance infrastructure levels and management systems have been realized. This has left room for the basic design and implementation of absolute new and effective technologies in countering most of these challenges as a way of realizing effective management of all civil infrastructures systems. Therefore, any management system for structure management for big infrastructure organizations will be required to incorporate a number of aspects that will improve infrastructure management (Lee & Shanmugam, 2001). With this assignment, the module will be suffucient in providing the students with an analytical skills which are coupled with practical applications and solutions in understanding the deterioration profiles of some common building and structural materials.
Basic Techniques Applied in Structural Assessment: Requirements
Inline with all the common infrastructure management practices like inspection, data collection, assessment of the conditions, and performance evaluation, prediction of future performances and evaluation for an alternative economic and technical policy, it is necessary to have an integrative and multidisciplinary approach towards infrastructure management. One of the infrastructure management systems that have been effectively used in large infrastructure organizations is known as the Four-Tier Component-Based Framework for Integrated Infrastructure Management Systems, FTCBFIIMS, (Nageim & MacGinley, 2005). This assessment system for large infrastructure has its functionality based on the concept that environment for all Infrastructure Management Softwares will have major similarities in their characteristics. Although some differences may as well occur, the definition of a common architecture for the software classification becomes something very necessary. For instance, the above mentioned system is a computational software model which provides some main domain-specific operations and services required in the maintenance of infrastructure management softwares.
The framework of this model is based on a number of reusable components which utilise some functionality which are domain-specific like in their operations. Also, there is an effective management of information which can effectively be applied in the management of specific infrastructure systems like bridges, sewers, or pavements should the model be specifically implemented. The common architectural design of the system will definitely result in an improved re-usability and interoperability of various structural components and also improve consistency in the domain application (Salon & Johnson, 2008). This model is also known to integrate the use of GIS, Geographic Information Systems functionality together with its supported linkages through adoption of Computerized Maintenance Management Systems, CMMS. Why is this use of Geographic Information Systems very vital? The use of GIS technology will be effective in enabling the querying processes, visualization, exploration, and analysis of the infrastructure from a spatial perspective. On the other hand, the CMMS systems will result in drastic improvements of a country’s economy, bring about efficiency in the maintenance of all the integrated infrastructure management systems. The overall combination of GIS and CMMS systems will contain the major components for effective structural maintenance and inspection system, and hence can be effectively applied in large infrastructure organizations (Trahair, 2008).
Therefore, the integration of computer managed GIS and CMMS systems may be some of the vital requirements for infrastructure management in large infrastructure organizations. The other requirement is in keeping of records that will reflect the results obtained from each and every assessment. The keeping of these records should be done in an intelligent manner so that they can effectively highlight some of the defects’ initiations, the deterioration processes, and how the deterioration can be propagated (Nageim & MacGinley, 2005). This acts as a catalogue that aids the technicians in carrying out their routines or even thorough inspections in the structures in order to make decisions in a most reliable way regarding the recorded processes of deterioration, the cause of the deterioration, and the anticipated damage on the structure.
However, the final identification or the classification of the damages being identified has to be based on technical engineering judgmental principles, appropriate expertise and be done by experienced inspectors. It will be agreed that any damage and deterioration of structures like bridges will definitely hinder their carrying capacity and the reason this monitoring is quite fundamental. Accessibility of the system should also be made available to all relevant personnel for effective structure assessment. Just to summarize, the assessment will only be requirement if the necessary requirements like the provision for comprehensive solutions in the monitoring, inspecting, and decision-making are made easier. In addition, the system has flexible integration and reporting between asset managers to the key decision makers concerning the structural planning, servicing departments, and involvement of the citizens and the stakeholders (Mosely et. Al, 2007).
Common Defects in Structures: Causes and Repair
Deterioration of building and huge structures will definitely result in functionality, durability, and reliability problems with the structures. There are factors that will highly cause structural deteriorations. These ranges from the engineering design applied in the construction, the materials used in construction of the structure, and the methods used. In addition, the weight and loads suspended on the structure will also influence the rate of deterioration of a structure. The maintenance services applied to a given structure and the environmental conditions affecting that given structure will greatly affect the structure in terms of its durability (Lee & Shanmugam, 2001).
Some defects resulting from the design of a structure may result from the obsolete art state and design codes or standards that had been applied in the structural designing. These designs may have been outdated especially on some parts, which may end up resulting in leakages and eventually degrading the concrete. For example, a leaking pipe somewhere within the concrete will cause deterioration of the structure (Mazzolani & Ballio, 2003). Prolonged environmental and weather conditions will also cause defects in large civil structures, and this may be because of frost, pollution and increased temperatures. The materials that were used in the building and construction of a given structures will effectively contribute to the enhancement of defects in the structure. For instance, using materials like structural steel and concrete not meeting the design specifications and requirements will result in a number of problems when it comes to bearing of load and durability. Sub-standard materials used as if cement and timber may succumb to the prevailing environmental conditions hence weakening the structure.
Some other defects will result during the construction process, and these may include the placement of some inadequate reinforcements hence causing unnecessary cracks, deflections, and collapse in extreme cases. Another important source of defects is with loadings, which will result in the development of some key defects in a structure hence weakening it. Additionally, some serious mechanical defects in structures may result from earthmoving vehicles and trains. In addition, some natural disasters in the environment like floods, falling rocks, floods, earthquakes and landslides will damage structures (Martin & Purkiss, 2008). How do we repair some of these defects? Before any repairs are to be done, there should be appropriate assessment and analyse intensity of the defect, its cause, and then be able come up with better strategies and methods for repair. The use of carbon-fibre-reinforced patches of polymers has been applied in repairing a crack or any other kind of defect in thick-walled concrete reinforced with steel. Leakages will have to be repaired through welding and application of sold glues so that the damage may not continue. Any leaking parts of a roof will also need to be repaired by expert personnel (McKenzie, 2004). In case of bridges, it would be recommended that there should be an immediate re-building so that it may not pose any danger to the users.
Using the case study, it can be easy to assess the limiting bottom flange loss that can be safely accommodated without imposing a loading restriction on a single railway track bridge.
From the above, since there will be a 25 percentage in deterioration in the train pathway, it would be advised that this kind of defect is very harmful and may see a train derailed from track. In recommendation, the appropriate thing would be to come up with new steel which has not been deteriorated and which meets the requirements. In summary, it would be necessary for large organizations to have effective assessment and management systems, which will ensure that all defects in structures are reported accurately and immediately, and then possible solutions found instantly. In addition, it would be required that these systems meet all the requirements that have been given in the paper for effective assessment of structures through inspection and maintenance management in large infrastructure organisations.
Ambrose, J. & Parker, P. (2007). Simplified Design of Steel Structures. New York: John Wiley and Sons.
Lee, S. & Shanmugam, N. (2001). Steel structures: Recent Research and Developments. London: Taylor & Francis Publishing.
Martin, L. & Purkiss, J. (2008). Structural Design of Steelwork. New York: Heinemann.
Mazzolani, F. & Ballio, G. (2003). Theory and Design of Steel Structures. London: Taylor& Francis Publishing.
McKenzie, W. (2004). Design of Structural Elements. Palgrave: Macmillan.
Mosely, B., Bungey, J., Jimmy, K. & Hulse, R. (2007). Reinforced Concrete Design to Eurocode 2. Palgrave: Macmillan.
Nageim, H. & MacGinley, T. (2005). Steel Structures: Practical Design Studies. London: Taylor & Francis Publishing.
Salon, G. & Johnson, E. (2008). Steel Structures: Design and Behavior: Emphasizing Load and Resistance Factor Design. New Jersey: Prentice Hall.
Trahair, N. (2008). The Behaviour and Design of Steel Structures to EC3. London: Taylor & Francis Publishing.
Westbrook, R. & Walker, D. (1996). Structural Engineering in Practice. London: Longman.